If an organisation you're trading with requires a vendor number, you will be able to view or add it when accepting the community invitation.

You can always add your vendor number in your organisation's settings:

1. Go to your organisation by clicking on the building icon, or your organisation's name in the top right of the menu
2. In the navigation on the left, click organisation settings > general settings > identifiers
3. Below other identifiers, under community, select the community you're adding the vendor number for
4. Under identification scheme, select vendor number
5. Under identification value, enter your vendor number
6. Click save.

Note: If you are using a vendor number as your 'mock' GLN please select GLN in step 4.